Circuit interrupter



Oct. 28, 1952 R. c. DICKINSON ETAL 2,616,007

CIRCUIT INTERRUPTER Filed Jan. 4, 1947 2 SHEETSSHEET l Insu/af/on frlsu/a f/on NVENTOR 5 WHEETSSES' 6/ 5.? fF/nA and @errcipfckl'nson.

Patented Oct. 28, 1952 GIRCUIT INTEBRUPTER Robert C, Dickinson and Russell E. Frink, Bitts: burgh, 2a., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application January 4, 1947, Serial No. 720,165

8 Claims. 1

This invention relates to circuit interrupters in general, and more particularly to areextinguishing structures therefor.

It is a general, object of our invention to pro,- vide an improved circuit interrupter of the airbreak type involving improved plate configuration and improved magnetic blow-out structure.

A further object of our invention, is to provide an improved circuit interrupter in which the blow-out magnet is disposed intermediate the ends of the arc chute and is at a floating potential in the fully open circuit position of the interrupter.

Another object is to. provide an improved circuit interrupter of the air-break: typev in which an; interrupter is employed to interrupt a portion of the initial arc length upon the insertion of the blow-out coil into series circuit.

Another object is to provide an, improved circuit interrupter having a more effective blow-out magnet structure to more effectively utilize the iron structure than has been done heretofore.v

Another object is to provide an improved circuit interrupter in which the positioning of the several parts is such that improved operation of the interrupter is obtained.

Further objects and advantages will readily become apparent upon a reading of; the following specification, taken in conjunction with the drawings, in which :v

Figure l is a vertical sectional view through an improved air-break circuit interrupter embodying our invention and shown in the closed circuit position;

Fig. 2 is a vertical sectional. view taken substantially on the line II-II of Fig. 1;

Fig. 3 is a fragmentary vertical sectional view taken along the line IIIIII of Fig. 1;

Fig. 4 is a fragmentary sectional viewtaken along the line, IV.IY of Fig. 3 looking in the direction of the arrows; and

Fig. 5 is a diagrammatic view of'the-iron structure employed in our improved magnetic. blowout arrangement.

Referring to the drawings, and, more particularly to Fig. 1 thereof, the reference character I generally designates contact structure, which, when separated, produces an arc, which, because of the intrinsic loop circuit provided, expands in an upward direction to be extinguished in an arc-extinguishing chute structure generally designated by the reference numeral 2'. The arc chutestructure 2 is generally of the type set forth in United States patent application, Serial No. 514,362, filed Decemberlfi, 1943, now U. S. Patent 2,442,199, issued May 25, 1948 to Robert 2 C. Dickinson and Russell E. Frink, and assigned to; the assignee of the instant application.

The, contact structure I electrically bridges two terminal studs ii, 4, which are surrounded by suitably flanged insulating bushings 5, 5 which pass through supporting panel structure 7. The terminal studs. 3. 4 are employed to connect the circuit interrupter to auxiliary equipment, not shown, which it is desired to protect and control.

A contact plate 10 is secured to the inner end of the terminal stud t and serves as a base for rotative motion of a movable contact arm i i, the latter rotating about a pivot [2 by actuation of an insulating operating rod I3. The operating rod 13 is pivotally. connected at M to an outwardly extending portion I5 of the movable con tact. arm H.

Also associated with the terminal stud 3 is. a second stationary contact plate I6. A bridging bar 1! operatively connected with the movable contactarm ll electrically interconnects the stationary contact plates I0, [6 in the closed circuit position of the interrupter as shown in Fig. 1. The contact bridge or bridging bar [1 has a bolt |;8 passing therethrough which is threadedly secured to the contact arm i l. Preferably a spring [.9. is interposed between the contact arm i i and the main contact brid e ll to provide the desired contact pressure in the closed circuit position of the interrupter.

Disposed at the upper end of thecontact structure. l. are a pair of coacting secondary contacts 20., 2| and a cooperable pair of arcing contacts 22, 23. The construction is such that the second ary contacts 20, 2| separate following the separation of the contact, bridge I! from the stationary main contacts l0, IE, but prior to the separation of; the arcing contacts 22, 23.

During circuit'interruption, the are which is drawn between the arcing contacts 23 by virtue of clockwise rotative motion of the movable contact arm I! expands upwardly because of the loop circuit formed by the, terminal studs 3, 4; and the, contact structure I so that a portion of: the arc rises toward the transfer interrupter or transfer arc-extinguishing means, generally designated by the reference numeral 24. This portion of the arc is now substantially horizontal and is positioned between the sub-pole pieces 25, the latter depending downwardly from the main pole pieces 26.

A large part of the magnetic flux which encirclesthis portion of the are will be diverted through the sub-pole pieces 25, the main pole pieces 26 and the core 21 of the blow-out structure- 28, but it must all return through the air gap below the arc.

This means that in the region surrounding the arc the flux density is considerably higher below it than above it. The result is that the arc is forced upwardly into the transfer interrupter 24. The construction of the transfer interrupter 24 is more clearly shown in Figs. 1 and 2. From an inspection of these figures it will be apparent that the transfer interrupter 24 includes a plurality of spaced slotted plates 29 having the upper closed end of the slots 36 off center with respect to the center line 3! of the plate so that the alternate positioning thereof will form a staggered arc passage at the upper end of the slots 39, as more clearly shown in Fig. 2.

Thus the arc which is moved upwardly in'the slots 30 of the plates 29 of the transfer interrupter 24 is compelled to be elongated as it is stretched between adjacent plates 29 by the offset feature of the slots 30 of the plates 29.

The result of the forcing of the are into the slots 38 of the transfer interrupter 2% is the raising of the arc voltage between the transfer arc horns 32, 33 to a value higher than the voltage between these are horns 32, 33 would be if the short circuit current passing through the interrupter were flowing through the blow-out coil 34. The blow-out coil 34 is electrically connected between the transfer are horns 32, 33.

This causes the arc to be quickly transfererd to I the blow-out coil 34 and to be extinguished over fer arc horn 33 and the movable arcing contact 23, as clearly shown in Fig. 1, the arc portion 35 extending between the transfer arc horns 32, 33 within the transfer interrupter 24 being extinguished.

The current which now passes through the blow-out coil 34 energizes the main magnetic field which passes through the core 27, to the right and to the left along the main pole pieces 26. The result is a strong transverse magnetic field through the plate structure til which causes the outer ends of the arm portions 31, 38 to transfer respectively to the panel-end arc horn ll and the outer arc horn 42. Th position of the two are portions is now represented by the reference numerals G3, 44.

The transverse magnetic field set up by the main pole pieces 26 quickly moves the arc portions 43, 44 upwardly along the respective arcing horns Al, 32 and 33, 42 into the two plate structures or arc-extinguishing sections 40.

The construction of each plate structure 49 is more clearly apparent upon consideration of Figs. 1 and 3. Referring to Fig. 3, it will be observed that the plate structure as includes a plurality of spaced slotted plates 45 with inverted closed slots 46 provided therein. The upper closed ends of the slots 46 are positioned unsymmetrically about the center line 31 of the plates 45. The result of the alternate positioning thereof is a staggered arc passage along the upper closed ends of the slots 46, as more clearly shown in Fig. 3.

Referring to Fig. 5, it will be seen that the total flux through the core 27 divides and goes half in each direction. The result is that high field strengths can be obtained Without using large, heavy, expensive magnets. This follows inasmuch as when the core is at one extremity of the pole pieces the total flux passing between the pole pieces must pass through the portion of the pole pieces immediately adjacent to the core. The result of such a construction is increased cross-sectional areas of the pole pieces immediately adjacent to the core. Furthermore, the flux distribution is not as uniform as might be desired.

With our construction having th core 2i disposed intermediate the ends of the main pole pieces 26, the iron is more effectively utilized inasmuch as the flux after passing through the core 21, passes in opposite directions through the main pole pieces 26.

Furthermore, with our improved construction the blow-out coil 28 and the magnet are floating at all times when highvoltage is applied across the terminals of the breaker. A distinct advantage follows inasmuch as the puncture voltage must pass through two thicknesses of the insulating jacket about the arc chute. in other words, the puncture voltage must penetrate from the arc horn t! through the insnulating side plate 49 to the pole piece 26 and then back through the side plate 8 to strike the other are horn 42 which is at the opposite line potential.

Suitable venting means are provided for the transfer interrupter 24 by cutting windows 52 through the arc chute and magnet directly above the interrupting plates 29. The end plates 53 of the transfer interrupter 2d are extended upwardly beyond the other plates 29 and are sealed into the material above the interrupter 2G by means of notches 54 provided in the horizontally extending insulating plate 55. These end plates 53 act as a barrier to prevent the incandescent gases from the main arc portions :33, iii from entering the space above the transfer interrupter 24 and causing the are 35 which it has extinguished from re-igniting over the top edges of the plates.

Also, without these barriers 53, the products of decomposition of the main arc portions as, G l escaping through the venting windows 52 is sufficiently severe to require a flame suppressor, if it were not stopped in another manner, such as by the barrier plates 53.

The resistor 5?, which shunts the blow-out coil 3G, and is directly connected across the transfer arc horns 32, 33, is not necessary to the operation of the interrupting device, but its presence improves performance.

We believe that the improved performance of our invention is accomplished by: (a) Much higher field strengths for a given quantity of iron, (b) more uniform field strength over the length of the interrupter, (0) rapid, positive, complete transfer of current to the blow-out co' and (d) blow'out field at zero current due to the presence of the shunting resistor M.

The foregoing interrupter which we have described results in an improved circuit interrupter which gives double the field strength without increasing the pole unit width and provides posi-- tive and rapid transfer of the short circuit current to the blow-out coil 35 to thereby provide increased insulation strength without increasing the quantity of insulating material, and greatly increases the interrupting ability of a given unit.

We claim as our invention:

1. A circuit interrupter including contact structure for establishing an arc, a, pair of terminals of opposite polarity, an arc chute for extinguishing. the are including twoplate structures, each plate structure including a plurality of spaced insulating plates positioned substantially perpendicularly to the direction of the arc, a pair of arc horns disposed at opposite ends of the two plate structures and electrically connected at least during arc extinction to the terminals of opposite polarity, magnetic blowout structure including a pair of magnetic pole plates on opposite sides of the two plate structures extending in a direction substantially perpendicularly to the plates, a magnetic core disposed between the two plate structures and interconnecting the magnetic pole plates to form a substantially H- type magnetic circuit, the magnetic core having an energizing winding thereabout,. the energizing winding being. at a floating potential with respect to the pair of arc horns in the fully opencircuit position of the interrupter, the energizing winding having a pair of transfer arc horns electrically connected thereto at th opposite ends thereof, said winding being de-energized in the, closed circuit position of the interrupter, each of, the pole plates having a portion extending to a point immediately adjacent to th contact structure so that during the opening operation of the interrupter, even before the energizing winding has current flowing therethrough, the magnetic field set up by the established arc will be affected by the portions to concentrate magnetic flux in the pole plates to thereby cause initial movement of the arc.

2. A. circuit interrupter including contact structure for establishing an arc, a pair of terminals of opposite polarity, an arc chute for extinguish.- ing the are including two plate structures, each plate structure including a plurality of spaced insulating plates positioned substantially perpendicularly to the direction of the arc, a pair of arc horns disposed at opposite ends of the two plate structures and electrically connected. at least during arc extinction to the terminals of opposite polarity, magnetic blowout structure including a pair of magnetic pole plates on opposite sides of the two plate structures extending in a direction substantially perpendicularly to the plates, a magnetic core disposed between thetwo plate structures and interconnecting the magnetic pole plates. to form a substantially H type magnetic circuit, the magnetic core having an energizing winding thereabout, the energizing winding being at a floating potential with respect to the pair of arc horn in the fully open circuit position of the interrupter, the energizing winding having a pair of transfer are horns electrically connected thereto at the opposite ends thereof, said winding being de-energized in the closed circuit position of the interrupter, said winding when energized causing magnetic flux to pass through the pole plates in a direction substantially perpendicularly to the plates and also causing magnetic flux to pass between the plates of the two plate structures from one pole plate to the other, each of the pole plates having an appending portion centrally located with respect to the arc chute which extends to a pointimmediately adjacent to the contact structure so that during the opening operation of the interrupter, even before the energizing winding has current flowing therethrough, the magnetic field set up by the established arc will be affected by the centrally located appending portions to concentrate magnetic flux in the pole plates to thereby cause initial movement of the arc.

3. A circuit interrupter including contact structure for establishing: an are, anarcchute for extinguishing the: are including arc-extinguishing means at leastpartly of insulating material, magnetic blowout structureincluding a pair of magneticpole plates on-opposite sides of. the arc chute extending-lengthwise ofthe arc chute, a magnetic core interconnecting the magnetic pole plates and having an. energizing winding thereabout, said" winding beingv substantially deenergized in the closed circuit position of the interrupter, each of. the pole plates having a pole portion extending, to a point, immediately adjacent to the contact structure, said two pole portions being magnetically connected by said core, a transfer arcextinguishing means disposed between said pole portions and having at least one transfer arc horn electrically connected to said energizing winding, the two pole. portions functioning during the opening operation, even before the energizing winding has current flowing therethrough, to affect the magnetic field set up by the established arc to. concentrate magnetic flux in the pole plates to. thereby bias the are into the transfer arc-extinguishing means.

4. A circuit interrupter including contact structure for establishing an are, an arc chute for extinguishing. the arc: including arc-extinguishing means at least partly of insulating material, magnetic blowout structure including a pair of magnetic pole plates on opposite sides of the arc chute extending lengthwise of the arc chute, a magneticcore interconnecting the magnetic pole plates. and having an energizing winding thereabout, said winding being substantially de-energized in the closed circuit position of the interrupter, said winding when energized causing magnetic flux to pass through the pole plates lengthwise of the arc chute and also causing magnetic flux to pass between the pole plates from one pole plate across the arcchute to'the other pole plate, each of thepole plates having an appending pole portion centrally located with respect to the arc chute which extends to a point immediately: adjacent to the contact structure, said two appending pole portions being magnetically connected by said core, a transfer arc-extinguishing means disposed between saidpole portions and having at least one transfer are horn electrically connected to said energizing winding, the two centrally located pole portions functioning duringtheopening.operation, even before the energizing winding has current flowing therethrough, to affect the magnetic field set up by the. established arc to concentrate magnetic flux in the pole plates to thereby bias the arc into the transfer arc-extinguishing means. 7

5. A circuit interrupter-including contact struc ture for establishing an arc, a pair of terminals of opposite. polarity, an arc chute for extinguishing. the are including two. arc-extinguishing sections, each arc-extinguishing section being at least; partly of insulating material, a pair of arc horns. disposed at opposite ends of the two arcextinguishing; sections and electrically connected at least during arc extinction to the terminals of opposite polarity, magnetic. blowout structure including a pair. of; magnetic. poleplates on opposite sides of the two arc-extinguishing sections extending. in a direction lengthwise of the arc extinguishing sections, a magnetic core disposed between. the. two. arcrextine'uishing sections and interconnecting; he: ma netic. pole plates to form asubstantiall-y' H- type-magnetic circuit, the magnetic core having an energizing winding thereabout, the energizing winding being at a floating potential with respect to the pair of arc horns in the fully open circuit position of the interrupter, the energizing winding having a pair of transfer are horns electrically connected thereto at the opposite ends thereof, said winding being de-energized in the closed circuit position of the interrupter, each of the pole plates having a portion extending to a point immediately adjacent to the contact structure so that during the opening operation of the interrupter, even before the energizing winding has current flowing therethrough, the magnetic field set up by the established arc will be affected by the portions to concentrate magnetic flux in the pole plates to thereby cause initial movement of the are.

6. A circuit interrupter including contact structure for establishing an arc, a pair of terminals of opposite polarity, an arc chute for extinguishing the are including two arc-extinguishing sections, each arc-extinguishing section including means at least partly of insulating material, a pair of arc horns disposed at opposite ends of the two arc-extinguishing sections and. electrically connected at least during arc extinction to the terminals of opposite polarity, magnetic blowout structure including a pair of magnetic pole plates on opposite sides of the two arc-extinguish ing sections extending in a direction lengthwise of the rc-extinguishing sections, a magnetic core disposed between the two arc-extinguishing sections and interconnecting the magnetic pole plates to form a substantially H type magnetic circuit, the magnetic core having an energizing winding thereabout, the energizing winding being at a floating potential with respect to the pair of arc horns in the fully open circuit position of the interrupter, the energizing winding having apair of transfer are horns electrically connected thereto at the opposite ends thereof, said winding being ale-energized in the closed circuit position of the interrupter, said winding when energized causing magnetic flux to pass through the pole plates in a direction. substantially lengthwise of the arcextinguishing sections and also causing magnetic flux to pass across the arc-extinguishing sections from one pole plate to the other, each of the pole plates having an appending portion centrally located with respect to the arc chute which extends to a point immediately adjacent to the contact structure so that during the opening operation of the interrupter, even before the energizing winding has current flowing therethrough, the magnetic field set up by the established arc will be affected by the centrally located appending portions to concentrate magnetic flux in the pole plates to thereby cause initial movement of the are.

7. A circuit interrupter including contact structure for establishing an arc, a pair of terminals of opposite polarity, an arc chute for extinguishing the are including two arc-extinguishing sections, each arc-extinguishing section including means at least partly of insulating material, a pair of arc horns disposed at opposite ends of the two arc-extinguishing sections and electrically connected at least during arc extinction to the terminals of opposite polarity, magnetic blowout structure including a pair of magnetic pole plates on opposite sides of the two arc-extinguishing sections extending lengthwise of the arcextinguishing sections, a magnetic core disposed between the two arc-extinguishing sections and interconnecting the magnetic pole plates to form a substantially H type magnetic circuit, the magnetic core having an energizing winding thereabout, the energizing winding being at a floating potential with respect to the pair of arc horns in the fully open circuit position of the interrupter, the energizing winding having a pair of transfer are horns electrically connected thereto at the opposite ends thereof, transfer arcextinguishing means associated with said transfer are horns, said winding being de-energized in the closed circuit position of the interrupter, each of the pole plates having a portion extending to a point immediately adjacent to the contact structure, said transfer arc-extinguishing means being disposed between said portions so that during the opening operation of the interrupter, even before the energizing winding has current flowing therethrough, the magnetic field set up by th established. arc will be affected by the portions to concentrate magnetic flux in the pole plates to thereby bias the arc into the transfer arcextinguishing means.

8. A circuit interrupter including contact structure for establishing an are, a pair of terminals of opposite polarity, an arc chute for extinguishing the are including two arc-extinguishing sections, each arc-extinguishing section including arc-extinguishing means at least partly of insulating material, a pair of arc horns disposed at opposite ends of the two arc-extinguishing sections and electrically connected at least during arc extinction to the terminals of opposite polarity, magnetic blowout structure including a pair of magnetic pole plates on opposite sides of the two arc-extinguishing sections extending in a direction lengthwise of the arc-extinguishing sections, a magnetic core disposed between the two arc-extinguishing sections and interconnecting the magnetic pole plates to form a substantially H type magnetic circuit, the magnetic core having an energizing winding thereabout, the energizing winding being at a floating potential with respect to the pair of arc horns in the fully open circuit position of the interrupter, the energizing winding having a pair of transfer arc horns electrically connected thereto at the opposite ends thereof, transfer arc-extinguishing means disposed between said transfer are horns, said winding being de-energized in the closed circuit position of the interrupter, said winding when energized causing magnetic flux to pass through the pole plates in a direction substantially lengthwise of the arc-extinguishing sections and also causing magnetic flux to pass between the pole plates, each of the pole plates having an appending portion centrally located with respect to the arc chute which extends to a point immediately adjacent to the contact structure, said transfer arc-extinguishing means being disposed between the two appending portions so that during the opening operation of the interrupter, even before the energizing winding has current flowing therethrough, the magnetic field set up by the established arc Will be affected by the centrally located appending portions to concentrate magnetic flux in the pole plates to thereby cause initial movement of the arc into the transfer arc-extinguishing means.

ROBERT C. DICKINSON. RUSSELL E. FRINK.

(References on following page) REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Hewlett Apr. 17, 1906 Carichofi Dec. 14, 1915 Terngren Dec. 9, 1919 Tritle Dec. 6, 1921 Aalborg June 29, 1926 Number 10 Number 

